Environmental Engineering Flashcards
A sanitary landfill is 210,000 square meters in area and 2 m deep. The daily loading of garbage is 800m3/day. What is the life at the landfill in years if the garbage is compacted in the landfill with twice its loading density?
A. 3 years
B. 13.3 years
C. 2.88 years
D. 16.3 years
C. 2.88 years
The ionic strength of 0.1 M solution of ferrous sulfate is
A. 0.75
B. 0.50
C. 1.50
D. 0.40 M
D. 0.40 M
Determine the equivalent weight of the following: Ca2+, CO32- and CaCO3
A. 20, 30 and 50 g/equi
B. 20, 40 and 50 g/equi
C. 20, 30 and 60 g/equi
D. 20, 40 and 60 g/equ
A. 20, 30 and 50 g/equi
How many milligrams per liter as CaCO3 is equivalent to 83 mg/L as Ca2+?
A. 200 mg/L
B. 156 mg/L
C. 168 mg/L
D. 95.3 mg/L
B. 156 mg/L
How many milligrams per liter as CaCO3 is equivalent to 220 mg/L as HCO3-?
A. 148 mg/L
B. 156 mg/L
C. 168 mg/L
D. 180 mg/L
D. 180 mg/L
Water from city well is analyzed and is found to contain 20 mg/L as substance of HCO3- and 40 mg/L as substance CO3-2. What is the alkalinity of this water in mg/L as CaCO3?
A. 75.7
B. 83.2
C. 89.7
D. 150 mg/L
B. 83.2
A water contains 100 mg/L CO3 and 75 mg/L HCO3 at a pH of 10 (T=25°C). Calculate the exact alkalinity (as mg CaCO3/L). Approximate the alkalinity by ignoring the appropriate chemical species.
A. 233 mg/L
B. 200 mg/L
C. 190 mg/L
D. 150 mg/L
A. 233 mg/L
Glutamic acid (C5H9O4N) is used as one of the reagents for a standard to check the BOD test. Determine the theoretical oxygen demand of 150 mg/L of glutamic acid. Assume the following reaction apply
C5H9O4N + 4.5O2 → 5CO2 + 3H2O + NH3
NH3 + 2O2 → NO3- + H+ +H2O
A. 18 mg/L
B. 190 mg/L
C. 198 mg/L
D. 212 mg/L
D. 212 mg/L
A 10mL sample of sewage mixed with enough water to fill a 300-mL bottle has an initial DO of 9 mg/L. To help assure an accurate test, it is desirable to have at least a 2 mg/L drop in DO during the five-day run, and the final DO should be at least 2 mg/L. for what range of BODs would this dilution produce the desired results? (unseeded five-day BOD test)
A. 60-210 mg/L
B. 100-200 mg/L
C. 60-150 mg/L
D. 120-210 mg/L
A. 60-210 mg/L
A test bottle containing just seeded dilution water has its DO level rop by 1.0 mg/L in a five-day test. A 300-mL BOD bottle filled with 15 mL of wastewater and the rest seeded dilution water (sometimes expressed as a dilution of 1:20) experiences a drop of 7.2 mg/L in the same time period. What is the five day BOD of the waste? (a seeded BOD test)
A. 144 mg/L
B. 125 mg/L
C. 210 mg/L
D. 300 mg/L
B. 125 mg/L
If the five-day BOD of a waste is 220 mg/L and the ultimate BOD is 320 mg/L, what is the rate constant?
A. 0.142/day
B. 0.178/day
C. 0.210/day
D. 0.233/day
D. 0.233/day
A sample of municipal sewage is diluted to 1% by volume prior to running a five-day BOD test. After 5 days, the oxygen consumption is determined to be 2 mg/L. what is the five-day BOD of the sewage?
A. 200 mg/L
B. 220 mg/L
C. 240 mg/L
D. 300 mg/L
A. 200 mg/L
If the 3-day BOD(BOD2) of a waste is 75 mg/L and the BOD decay constant, k1 is 0.345/day, what is the ultimate BOD?
A. 100 mg/L
B. 110 mg/L
C. 116 mg/L
D. 130 mg/L
C. 116 mg/L
Calculate the length of a chlorinating pipe line with diameter of 0.6 m require to kill 95% of the bacteria in waste water flowing at 0.05 cu. m/s. Tests shows that 95.33% kill is obtained in 5 minutes when treated with 5 mg/L Chlorine. Chlorine disinfection kinetics is given by the equation:dC/dt = kCt1.5 where C = a number of bacteria. Assume that the same concentration of chlorine is used in actual treatment operation.
A. 25.36 m
B. 32.5 m
C. 52.63 m
D. 56.23 m
C. 52.63 m
A surface water primarily for contact recreation such as bathing, etc.
A. Class A
B. Class SA
C. Class B
D. Class AA
C. Class B
The gas from sludge digestion tanks is mainly composed of
A. Nitrogen
B. carbon monoxide
C. hydrogen sulfide
D. methane
D. methane
A 6 mL wastewater sample is diluted by 294 ml water. If the initial dissolved oxygen is 9.1 mg/L and after 5 days is 2.8 mg/L, calculate its BOD.
A. 280 mg/L
B. 400 mg/L
C. 315 mg/L
D. 420 mg/L
C. 315 mg/L
A 5 ml wastewater sample was analyzed for its BOD content using the standard BOD test. Initial and fifth day dissolved oxygen was measured as 7.5 mg/L and 2.5 mg/L respectively. What is the BOD of this sample?
A. 30
B. 210
C. 150
D. 800
D. 800
Compute the theoretical oxygen demand (ThOD) of 108.75 mg/L of glucose?
A. 116 mg/L
B. 125 mg/L
C. 174 mg/L
D.150 mg/L
A. 116 mg/L
Alum, a coagulant of water, is
A. aluminum sulfate
B. sodium hydroxide
C. ferrous sulfate
D. magnesium sulfate
A. aluminum sulfate
Ozone, O3, filters out large amount of the ultraviolet and other dangerous radiations from the sun. It is found in the
A. troposphere
B. stratosphere
C. thermosphere
D. lithosphere
B. stratosphere
Which of the following are major components of photochemical smog?
A. NOx and hydrocarbon
B. Sox and hydrocarbon
C. ozone and oxygen
D. NOx, Sox and hydrocarbon
A. NOx and hydrocarbon
A wastewater contains 10 ppm of chloride ions, how many mg/L is it?
A. 10
B. 14
C. 30
D. 20
A. 10
The mass ratio of nitrogen to oxygen in air is
A. 3.77
B. 3.12
C. 4.12
D. 3.29
D. 3.29
In the National Standard of Drinking Water, the maximum allowable chlorine content is 0.2 ppm. What is the equivalent concentration in mg/L?
A. 20
B. 0.2
C. 100
D. 200
B. 0.2
What is found in hard water?
A. calcium, phosphorus and magnesium
B. calcium and magnesium
C. phosphorus and magnesium
D. calcium and phosphorus
B. calcium and magnesium
Calculate the “exact” alkalinity (in milligrams per liter as CaCO3) of water containing 120 mg/L of bicarbonate ion and 15 mg/L of carbonate ion, at a pH of 9.43.
A. 110.5 mg/L
B. 116.2mg/L
C. 123.4 mg/L
D. 128.9 mg/L
C. 123.4 mg/L
It is the term used to describe the over-abundance in the growth of algae in water due to the presence of excess nutrients.
A. eutrophication
B. biodegradation
C. stabilization
D. decomposition
A. eutrophication
A type microorganism used for monitoring the pathogenic property of water.
A. Acidity
B. Coliform
C. hardness
D. dissolved oxygen
B. Coliform
This phenomenon is described by the separation of hot and cold regions in a given stream.
A. Eutrophication
B. digestion
C. thermal stratification
D. decomposition
C. thermal stratification
The hardness of water is expressed as g/L of?
A. CaO
B. MgO
C. CaCO3
D. MgCO3
C. CaCO3
Which compound gives a foul (rotten egg) odor?
A. Hydrogen sulfide
B. carbon monoxide
C. methane
D. carbon dioxide
A. Hydrogen sulfide
How many milligrams per liter as CaCO3 is equivalent to 48 mg/L as CO2?
A. 98.5 mg/L
B. 102.4 mg/L
C. 109.2 mg/L
D. 112.4 mg/L
C. 109.2 mg/L
A 5-mL wastewater sample was analyzed for its BOD content using the standard BOD test. Initial and fifth day dissolved oxygen was measured as 7.5 and 4 respectively. What is the BOD of this sample?
A. 30
B. 150
C. 210
D. 300
C. 210
A 5-mL wastewater sample was analyzed for its BOD content using the standard BOD test. Initial and fifth day dissolved oxygen was measured as 7.5 and 2.5 respectively. What is the BOD of this sample?
B. 30
B. 150
C. 210
D. 300
D. 300
The BOD rate constant is 0.233/day for a municipal wastewater. The BOD5, was measured to be 250 mg/L. What is the ultimate BOD?
A. 320 mg/L
B. 345 mg/L
C.357 mg/L
D. 363 mg/L
D. 363 mg/L
Which of the following is a toxic heavy metal discharge from industrial operations involving plating and metal finishing?
A. Hexavalent chromium
B. spent acids
C. septic waste
D. scrap metals
A. Hexavalent chromium
A sanitary landfill has available space of 16.2 ha at an average depth of 10 m. Seven hundred sixty five m3 of solid waste is dumped at the site 5 days a week. This waste is compacted to twice its delivered density. Estimate the expected life of the landfill in years.
A. 15 yrs
B. 16.25 yrs
C. 17.10 yrs
D. 17.80 yrs
B. 16.25 yrs
The ionic strength of 0.1 M solution of ferric sulfate is
A. 0.75
B. 0.50
C. 1.50
D. 0.25
C. 1.50